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Why Do Moles on Skin Appear?

woman with moles on face

Our skin seems to have a life of its own. There are all sorts of spots and moles and freckles that appear on it, seemingly out of nowhere. The majority of these are benign (meaning they are not cancer). The most common types are moles, lentigines and freckles, but there are also keratosis and skin tags. However, when people talk about a “mole” they generally mean a mole, a lentigo or a freckle. Hence, let’s take a look at these three skin marks that you may encounter on your own body.

Moles
Skin moles are generally brown or black in color. They can be found anywhere on the skin. Some of them are singular, others appear in a cluster or group. The majority of moles develop when we are children, with some taking up to 30 years to develop. By the time you reach adulthood, you should have between 10 and 40 moles. Over the course of your lifetime, moles will change in size and color. Some will even grow hairs and others suddenly start to disappear.

Moles are caused by skin cells not spreading properly, choosing to cluster instead. The medical name for these cells is “melanocytes”. These melanocytes create pigment, with pigment being the molecule that colors our skin. When they are exposed to the sun, particularly during teenage years or when women are pregnant, they may turn darker in color.

There are various types of moles. Congenital nevi appear from birth and are extremely rare. Only about 1% of people have these. If the diameter of the congenital nevi is larger than the eraser on a pencil, a biopsy should be taken. These nevi are also more likely to become melanoma, which means they are cancerous.
Then, there are dysplastic nevi. These are larger moles with irregular shapes. Usually, their color is very uneven, with light edges and dark centers. People who have these often have more than 100 moles all over their body and are also at an increased risk of skin cancer. This is why, if they spot a change in their moles, they should have them checked straight away.

Lentigo
A lentigo is a darker, generally brown, spot on the skin. Lentigines are very common on Caucasian people, particularly those who have very fair skin. The major cause for lentigines is sun exposure, which is why we tend to see them in those parts of the bodies that are most commonly exposed to the sun (arms, shoulders, face, hands). Lentigines can run in the family, but they can also be caused by radiation therapy.

Freckles
Freckles are small and brown and are often seen as cute (except by those who have them). They are most commonly found on the arms and on the face. They are very common and pose no threat to health at all. Freckles often come and go, being more prominent during the summer months or other periods of time when there is extensive sun exposure. It is generally Caucasian people who develop these, and those with red or ginger hair are most prone to them, even developing them with minimal sun exposure. Freckles can also be caused by genetics. As with any mole freckle removal is possible.

Why Do Moles Appear?
As you can see, there are many answers to the question of how do moles appear. Generally, however, it is caused by the sun or genetics. Moles are perfectly normal and often nothing to worry about. However, you must get to know your moles and determine whether they are going through rapid changes or feel weird, in which case they do need to be checked out.

{ 1 comment… add one }
  • Margaret Hicks March 7, 2017, 3:34 am

    I have the flat black moles..my mom and adult children do to. It seems to be genetic. Thanks

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